1. Field of the Invention
The present invention relates to a tip seal dispenser valve for a pressurized container of viscous products such as viscous foods, household products, pharmaceuticals, cosmetics, and toiletries.
It is desirable to dispense certain products in a manner which preserves their sterility as well as their fluid conditon. For example, viscous medicines and other viscous pharmaceutical products such as salves, steroids, and petroleum jelly should be packaged and dispensed so that amounts which are not used remain sterile. Household products such as caulking compound, viscous glues and cements which dry out and harden when exposed to air should be packaged and dispensed so that amounts which are not used remain sealed from the atmosphere. Foods like cheeses, syrups, and desert toppings should be packaged and dispensed so that they do not become contaminated.
Further, many products are difficult to handle and use when removed from their container. It is beneficial to package these products so that they can be easily and conveniently dispensed in desired amounts and at locations where needed.
2. Desciption of the Prior Art
Most commonly used dispenser valves seat to close at a location inside of the container which packages the product to be dispensed. Once past the valve seat, the product must further travel through additional valve components before ultimately leaving the container. Therefore, product ordinarily remains in these components, is exposed to the atmosphere and, thus, is subject to contamination or hardening. This is particularly true of viscous products which do not rapidly evaporate.
Various solutions to the problem of product contamination have been proposed. One solution is found in a form of valve, typically known as a "tip seal" valve, which controls dispensing from a product container. Tip seal valves seat outwardly of the container at the point where product is dispensed. Therefore, there are no valve or container components which confine product outwardly of the valve seat where it is subject to contamination.
However, presently known tip seal valves have certain drawbacks. For example, U.S. Pat. No. 3,268,123 (Spatz) discloses a valve used in conjunction with a piston pump for a nonpressurized package. The valve includes a valve plug mounted to close a valve seat at the mouth of a nozzle. The valve plug is mounted with a piston through a lost-motion coupling to be moved to an open position prior to piston actuation. However, the plug is not firmly guided within the nozzle into sealing engagement with the valve seat. Since the Spatz device is primarily a pump rather than a valve for a pressurized container, problems of dispensing products having widely varying viscosities under continuous pressure are not considered. Similarly, problems of sealing a valve used on a pressurized container are not considered. Moreover, the Spatz device is complicated, having many moving parts, and is, therefore, expensive to make and assemble.
U.S. Pat. No. 3,777,947 (Klema) discloses a tip seal valve assembly, for a pressurized container, that includes a tubular valve body in which a piston is mounted. A portion of the piston projects out of the body through suitable slots and is engaged by an actuator tab which, when depressed, depresses the piston. This valve is also relatively complicated having a large number of parts which must be fabricated and assembled.
Still other tip seal valve constructions are disclosed in U.S. Pat. Nos. 3,406,944 (Barker); 3,450,316 (Barker); 3,489,323 (Hug); and 3,506,165 (Beard).